New recommendations are that we apply sunscreen every 30 minutes while out in bright sunlight to exposed skin areas. This is true any time of the year winter or summer. The winter months can be just as bad because sun light reflects off snow and ice. A lot of people do not prepare for this.
Many make up foundations now have SPF 15 sunscreen in them and I would highly recommend using this if you do not put a sunscreen on your skin before your foundation.